U.S. patent number 9,292,004 [Application Number 14/052,162] was granted by the patent office on 2016-03-22 for gong for striking-work device of a timepiece.
This patent grant is currently assigned to Societe anonyme de la Manufacture d'horlogerie Audemars Piguet & Cie. The grantee listed for this patent is Societe anonyme de la Manufacture d'horlogerie Audemars Piguet & Cie. Invention is credited to Jean-Daniel Luthi, Lucas Raggi.
United States Patent |
9,292,004 |
Raggi , et al. |
March 22, 2016 |
Gong for striking-work device of a timepiece
Abstract
A gong for a striking-work device of a timepiece. The gong
includes a spring blade forming a main body of the gong and is
adapted to act as a vibrating member so as to produce a sound
following an actuation. The spring blade includes at least one
opening formed in its main body. The invention also includes a
timepiece, such as a mechanical watch, comprising such a gong.
Inventors: |
Raggi; Lucas (St-Blaise,
CH), Luthi; Jean-Daniel (Russy, CH) |
Applicant: |
Name |
City |
State |
Country |
Type |
Societe anonyme de la Manufacture d'horlogerie Audemars Piguet
& Cie |
Le Brassus |
N/A |
CH |
|
|
Assignee: |
Societe anonyme de la Manufacture
d'horlogerie Audemars Piguet & Cie (Le Brassus,
CH)
|
Family
ID: |
49209285 |
Appl.
No.: |
14/052,162 |
Filed: |
October 11, 2013 |
Prior Publication Data
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|
|
Document
Identifier |
Publication Date |
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US 20140104994 A1 |
Apr 17, 2014 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
G04B
21/08 (20130101); G10K 1/10 (20130101); G04B
21/00 (20130101); G04B 23/028 (20130101) |
Current International
Class: |
G04B
21/08 (20060101); G10K 1/10 (20060101); G04B
21/00 (20060101); G04B 23/02 (20060101) |
Field of
Search: |
;368/243,267,269,271,272,273 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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702 145 |
|
May 2011 |
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CH |
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703 776 |
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Mar 2012 |
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CH |
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704 593 |
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Sep 2012 |
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CH |
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2 107 437 |
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Oct 2009 |
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EP |
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2 207 069 |
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Jul 2010 |
|
EP |
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2 463 731 |
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Jun 2012 |
|
EP |
|
Other References
Machine translation of EP2463731, retrieved from the internet Jun.
14, 2015. cited by examiner .
Machine translation of CH704593, retrieved from the internet Jun.
14, 2015. cited by examiner.
|
Primary Examiner: Miska; Vit W
Attorney, Agent or Firm: Christensen Fonder P.A.
Claims
The invention claimed is:
1. A gong for a striking-work device of a timepiece, the gong
comprising a spring blade forming a main body of said gong and
being adapted to act as a vibrating member so as to produce a sound
following an actuation, the spring blade of the gong consisting of
a wound wire having at least partially the shape of a circular arc
and comprising at least one opening formed in its main body,
wherein said at least one opening formed in the main body of the
spring blade of the gong is either non-filled or filled at least
partially by addition of a material other than that of the main
body of the spring blade, said other material used for the filling
of said at least on opening being selected from the group of
materials consisting of gold, silver, platinum, and a
non-ferromagnetic metal alloy.
2. The gong according to claim 1, wherein at least one opening
formed in the main body of the spring blade of the gong is a
through-opening.
3. The gong according to claim 1, wherein at least one opening
formed in the body of the spring blade of the gong is a blind
opening.
4. The gong according to claim 1, wherein at least one opening
formed in the body of the spring blade of the gong has an oblong
shape of variable length.
5. The gong according to claim 1, wherein at least one opening
formed in the body of the spring blade of the gong is formed in a
plane of movement of the spring blade.
6. The gong according to claim 1, wherein at least one opening
formed in the body of the spring blade of the gong is formed in a
plane perpendicular to a plane of movement of the spring blade.
7. The gong according to claim 1, wherein at least one opening
formed in the body of the spring blade of the gong is machined by
means of a cutting or ablation laser, by electrical discharge
machining, by micromachining, or by water jet.
8. The gong according to claim 1, wherein at least one
inertia-block is mounted on the spring blade of the gong.
9. The gong according to claim 1, wherein the cross section of the
main body of the spring blade of the gong is substantially
circular, oval, rectangular, or polygonal.
10. The gong according to claim 9, wherein a diameter of the cross
section of the main body of the spring blade of the gong lies in
the range of 0.2 mm to 1.2 mm.
11. The gong according to claim 1, wherein the main body of the
spring blade of the gong is fabricated of a metal material.
12. A timepiece comprising a gong according to claim 1.
13. The timepiece of claim 12, wherein it is a mechanical
timepiece, in particular a bracelet watch, equipped with a
striking-work, an alarm, an alert, or a repeater mechanism.
14. The gong according to claim 10, wherein the diameter of the
cross section of the main body of the spring blade of the gong lies
in the range of 0.4 mm to 0.8 mm.
15. The gong according to claim 11, wherein the metal material
comprises steel.
Description
RELATED APPLICATION
The present application claims priority to Swiss Patent Application
No. CH 02002/12 filed Oct. 15, 2012, the disclosure of which is
hereby incorporated by reference herein in its entirety.
FIELD OF THE INVENTION
The present invention relates to a gong for a striking-work device
of a timepiece, the gong comprising a spring blade forming a main
body of said gong and adapted to serve as a vibrating element in
order to produce a sound following an actuation.
BACKGROUND
This type of device has long been known in principle. Striking-work
timepieces having been common in times past because they are able
to deliver auditory information concerning the current time during
the night or in darkness. Since the arrival of radium, fluorescent
dials, and other means for illuminating the dial making it possible
to read the time adequately even in darkness, thus simplifying the
construction, the creation, and the use of watches, the integration
of striking-work mechanisms, due to the complication of the
corresponding movements as well as the horological skill necessary
for their production, has become a subject reserved for
top-of-the-range timepieces. The manufacture of striking-work
mechanisms, in particular gongs, until recently therefore was
hardly developed and was based on a predominantly empirical
know-how, which resulted in a variability of the sound of the
produced striking-work watches.
In general, a striking-work mechanism of a watch is formed of at
least one gong and a hammer, which strikes, following its
actuation, against the gong so as to vibrate the gong. The gong
often has the form of a circular arc so as to advantageously
surround the movement of the watch by being placed in a plane
parallel to the dial of the watch. It is normally formed by a wound
metal wire, one of its ends being fixed to a blom stud, itself
mounted rigidly on a plate of the watch, whereas the other end
generally remains free. In some embodiments, the blom stud is
connected to the middle so as to promote the sound transmission.
The gong therefore acts as a resonator and the blom stud transmits
the vibration of the gong to the plate of the watch, thus enabling
a radiation of the sound waves, which are audible to the user in
the form of a generated sound.
Normally, a striking-work watch comprises two gongs, the hour gong
and the minute going, but may also comprise three or four gongs,
which is known by the name of a chime, and may even comprise more
gongs. The corresponding conventional gongs primarily differ in
diameter and in length so that the sound generated is different,
for example deep for the hour gong and high for the minute
gong.
In order to produce the desired sound, in particular with regard to
the tonal pitch thereof, its frequency composition and its
difference compared to the sound produced by other gongs present in
the watch, the amplitude, the period of the vibrations, and also
the length of the gong have to be carefully adjusted. In fact, if
the rigidity of the gong is excessive, the gong will not vibrate
sufficiently. If, by contrast, the gong is too soft, the sound
produced therefore will not be satisfactory.
These problems have only recently been studied in greater detail in
the horological industry, and less empirical efforts in nature have
been undertaken in order to develop gongs that produce a sound of
which the frequency composition is determined beforehand.
In fact, the spectrum of a musical sound is generally composed of a
base frequency, the first harmonic, and several harmonics which are
integer multiples of the base frequency. The sound produced by an
instrument may also comprise frequencies which are not integer
multiples of the base frequency and are called partial frequencies.
With regard to the horological field and the gongs of striking-work
mechanisms, the vibration of the gong or the frequency composition
of the sound thus produced normally comprises a number of partial
frequencies. In particular, the base frequency perceived during the
actuation of a striking-work does not correspond to the first
characteristic frequencies of the gong itself. Hereinafter, the
term base frequency means the tonal pitch perceived. This thus
results from a combination of the spectral components contained in
the vibratory behavior of the gong and the elements associated
therewith in the chain of wave propagation at the origin of the
sound.
The presence of partial frequencies in a sound can be perceived by
a human as pleasant or unpleasant depending on the number of
partial frequencies and their respective positions in the spectrum.
The totality of the spectrum formed by the different harmonics and
partial frequencies determines the tonal pitch of the sound as
perceived by a human. In addition, the human perception of the
sound depends not only on the number and position of the partial
frequencies, but also on their amplitude. This may create discord
or, on the contrary, harmony regarding the human perception of the
sound produced. Generally, it is considered that the three first
partial frequencies contribute to determining the tonal pitch and
that the following partial frequencies determine the timbre of the
sound, which is commonly called the richness, beauty or color of
the sound.
In particular, the frequency composition of a sound produced by a
gong, and therefore the frequency position of the harmonics and
partial frequencies, can be influenced by the choice of the
material, that is to say the physical properties, and also by the
choice of the geometry of the gong. For a given geometry of the
gong, the choice of the material allows to modify the position of
the base frequency perceived and the color of the sound. The
position of a harmonic modifies the vibration of the gong. The
damping of one or more vibration modes can be influenced as a
result. The frequency distribution of the partial frequencies
always follows the same law in this case. The choice of the
geometry of the gong for its part allows to modify the ratios
between the partial frequencies, for example by modifying the
rigidity of the gong.
Based on these facts, the above-mentioned efforts, which have been
undertaken in recent years by the horological industry so as to
enable the production of gongs generating a sound well determined
beforehand, in particular in terms of its tonal pitch and frequency
composition, concerned either the choice of material or the choice
of geometry of the gong.
For example, document EP 2 107 437 proposes the use of precious
materials such as gold or silver for the fabrication of gongs, this
due to the physical properties of these materials with regard to
the modulus of elasticity relative to their mass density, thus
enabling the production of a sound having an increased number of
partial frequencies. As mentioned above, the choice of the material
does, however, not allow the frequency distribution of the partial
frequencies relative to one another and thus remains a parameter
having relatively little potential of alone achieving all the
desirable characteristics of a gong.
Consequently, further efforts have been directed to the
modification of the geometry of the gong, for example as described
in document U.S. Pat. No. 7,746,732. Such a gong has a cross
section that is variable at least in part along its longitudinal
axis, for example continuously or by a succession of increases and
decreases in its cross section. Although the quality of the sound
can thus be improved, the fabrication of such a gong remains rather
complicated and unsuitable for production on an industrial
scale.
Another example of an effort targeting a specific gong geometry is
disclosed in document CH 702 145. A gong as proposed in this
document comprises a middle part having at least two different
cross-sectional portions. This gong is based on the same principle
as document U.S. Pat. No. 7,746,732, the variation of the cross
section of the gong, apparently by simplifying the embodiment of
the corresponding gong. However, it is not obvious whether this
proposition allows to obtain an improvement in terms of the sound
produced simultaneously with a simplification of the production
process, also because the different cross-sectional portions are
formed by metal wires having different diameters assembled by
brazing or soldering. In fact, this should lead either to a rather
complex production process in terms of the brazing or soldering
method or to a reduction in the quality of the gong obtained.
The prior art solutions currently known therefore either have a
rather complex structure preventing acceptable production of the
corresponding gongs or do not allow to obtain a gong having all the
desirable characteristics with regard to the quality to the sound
produced.
SUMMARY
There is thus still a need to provide a gong for a striking-work
device of a timepiece of the above-mentioned type of which the
structure is relatively simple and which nevertheless allows to
generate a sound well determined beforehand, in particular with
regard to its tonal pitch and its frequency composition, due to the
fact that the amplitude and period of the vibrations of the gong
that will be produced following an actuation under predetermined
conditions are carefully adjusted during the production of said
gong. In addition, it is desirable if such a gong can have not only
predefined properties with regard to the tonal pitch and the
frequency composition of the sound generated, but if it is also
possible to adjust the difference of the sound generated compared
to the sound produced by other gongs present in the watch, that is
to say to adjust the harmony between different gongs provided in a
given striking-work mechanism, or even by taking into account the
wishes of an individual user, who is normally the purchaser of the
corresponding timepiece. These objectives should be achieved while
ensuring reasonable production costs and simple integration into
known striking-work mechanisms.
The object of the present invention is therefore to overcome the
disadvantages of the known gongs and to provide the above-mentioned
advantages, in particular to enable the production of a
striking-work which is of simple design and which has an amplitude
and a period of vibrations predetermined during its fabrication,
thus producing a sound having a tonal pitch, a frequency
composition, and a difference compared to other gongs, adjusted
beforehand.
To this end, the present invention proposes a gong of the
above-mentioned type, in particular for integration into a
striking-work device of a mechanical timepiece, said gong being
distinguished in an embodiment by the features specified in claim
1, and also a corresponding timepiece comprising such a gong. In
particular, the spring blade of a gong according to the present
invention comprises at least one opening formed inside its main
body. These openings can be through-openings or blind openings. The
shape and size of these openings can be adapted according to
requirements, as can the plane in which they are arranged. The
openings are preferably machined by means of a cutting laser or an
ablation laser, by electrical discharge machining, by
micromachining, or by water jet, or by any other suitable
process.
In an embodiment of the gong according to the present invention, at
least one of these openings can be filled at least in part by
addition of a material other than the material in which the main
body of the spring blade is fabricated. The filling material for
example may consist of gold, silver, platinum, or a metal
alloy.
The shape of the cross section of the main body of the spring blade
of the gong, the shape of the gong itself, and also the material of
the main body of the spring blade can be selected according to
requirements.
As a result of these measures, the geometry and the material
composition of the gong is modified locally, and therefore its
rigidity, which allows to influence the vibratory behavior of the
gong following an actuation. Due to the fact that a gong according
to the present invention can thus be adapted to requirements both
by varying the geometry of the gong and, where necessary, by
modifying the material forming the gong, it is possible to
influence the sound produced by the gong with an increased level of
precision.
Further features and the corresponding advantages will be described
in greater detail in the dependent claims and also in the
description of the invention provided hereinafter.
BRIEF DESCRIPTION OF THE DRAWINGS
The accompanying drawings show schematically and by way of example
a number of embodiments of a gong according to the present
invention.
FIG. 1a shows a schematic plan view of a traditional structure of a
striking-work mechanism comprising gongs and hammers, mounted on
the frame of a timepiece;
FIG. 1b is a perspective view of an embodiment with two
superimposed gongs in their state fixed to a blom stud;
FIGS. 2a and 2b show schematically and by way of example, by
perspective views from above, two embodiments of a gong for a
striking-work mechanism according to the present invention, the
gong comprising openings inside its main body;
FIGS. 3a and 3b show schematically and by way of example, by
perspective views from above similar to FIGS. 2a and 2b, two
embodiments of a gong for a striking-work mechanism according to
the present invention, the gong comprising openings inside its main
body, of which at least one is filled with a material other than
that of the main body;
FIGS. 4a to 4c schematically and by way of example illustrate, by
perspective views from above, a number of embodiments of a gong for
a striking-work mechanism according to the present invention, the
gong comprising openings inside its main body as well as at least
one inertia-block mounted on the spring blade of the gong, and in
some embodiments at least one opening being filled with a material
other than that of the main body;
FIG. 5, by way of a basic diagram, shows a step during the
production of a gong for a striking-work mechanism according to the
claimed invention by means of a cutting laser.
DETAILED DESCRIPTION
The invention will now be described in detail with reference to the
accompanying drawings illustrating a number of embodiments of the
invention by way of example.
A striking-work gong according to the present invention is to be
integrated into a timepiece, in particular into a mechanical
bracelet watch. The schematic plan view in FIG. 1a shows the
conventional structure of a striking-work mechanism comprising two
gongs 1a, 1b and two corresponding hammers 2a, 2b, mounted on the
frame of a timepiece. Each gong 1a, 1b is fixed at one of its ends
on a blom stud 3 serving as a gong support and itself mounted on a
plate 4 of the timepiece, which is illustrated by way of example in
FIG. 1a as a bracelet watch. The other end of each gong 1a, 1b is
free. Each gong 1a, 1b is arranged in a plane parallel to the dial
of the watch, arranged above the plate 4, and extends along a
circular arc around the movement of the watch, which is not
illustrated in FIG. 1a for reasons of simplification. Each gong 1a,
1b is preferably formed by a wound metal wire forming said circular
arc. Once the striking-work mechanism is wound by means of a
push-piece 5, the striking-work is released. To this end, the
hammers 2a, 2b serving, for example, as an hour hammer 2a and a
minute hammer 2b and possibly having different masses are moved
alternately by the striking-work mechanism. Said mechanism will not
be described here since it does not form the subject of the present
invention. During its movement, each hammer 2a, 2b normally carries
out a partial rotation in the plane of the corresponding gong 1a,
1b and strikes said gong, thus producing a vibration of the gong
1a, 1b. The propagation of the vibration of the gong 1a, 1b through
the blom stud 3 as far as the plate 4 then produces sound waves, of
which some are in the spectrum audible for a human.
FIG. 1b is a perspective view of an embodiment with two
superimposed gongs, in their state fixed to the blom stud 3. As can
be seen from FIG. 1b, the gongs 1a, 1b may, for example, have the
same diameter at their circular arc and may be arranged in two
superimposed planes at a safety distance ensuring that they do not
touch during their vibration. Alternatively, their diameters formed
by the corresponding circular arc may be different so as to make it
possible to arrange the two gongs in the same plane, as shown in
FIG. 1a. In general, proceeding from the conventional structure of
a striking-work mechanism as illustrated in the figures, and of a
corresponding gong, a gong 1 according to the present invention may
have any shape, whether a partial circular arc or a straight form
along a linear generator or even another specific geometry.
In fact, as is shown schematically and by way of example in FIGS.
2a and 2b, which, by perspective views from above, show two
embodiments of a gong for a striking-work mechanism according to
the present invention, a gong 1 according to the present invention
comprises a spring blade 1.1 forming a main body of said gong 1 and
adapted to serve as a vibrating member in order to produce a sound
following an actuation, for example, by means of a hammer 2. In
particular, such a gong 1 distinguishes by the fact that the spring
blade 1.1 comprises at least one opening 1.2 formed inside its main
body.
In a first embodiment illustrated in FIG. 2a, the gong 1 has two
oblong through-openings 1.2 arranged approximately in the middle
and at the end of the first quarter along the circular arc forming
the spring blade 1.1 of the gong 1. The two openings 1.2 have
approximately the same length along the longitudinal axis of the
spring blade 1.1 of the gong 1, although this is not necessary,
their respective length being selected depending on requirements.
Likewise, the width of these openings 1.2 is identical in the
illustrated example, although this is not necessary. This width of
the openings 1.2 formed in the main body of the spring blade 1.1
may, in general, be selected in a range between approximately 10%
and 85%, preferably between 10% and 40%, of the diameter of the
spring blade 1.1, also depending on requirements. In a second
embodiment illustrated in FIG. 2b, the gong 1 has three oblong
through-openings 1.2, of which two correspond substantially to the
openings formed in the first embodiment of the gong 1 and of which
the third opening, having a much shorter length, is arranged
towards the end of the gong 1 assembled on the blom stud 3, this
zone subsequent to the setting of the gong 1 in the blom stud 3
being referred to conventionally as the heel of the gong. A gong 1
comprising at least one such opening 1.2 has the advantage that it
is possible to modify locally and precisely its geometry so as to
determine beforehand the vibratory behavior of the gong 1. In
addition, the openings 1.2 increase the radiating surface during
the vibrations of the gong 1, which may also be favorable for
production of a sound having a tonal pitch and of a gong as
desired. The targeted modification of the spring blade 1.1 of the
gong 1 by creating openings 1.2 thus allows to influence the
amplitude and period of its vibration, thus allowing to determine
during a production step, commonly called the tuning of the gong 1,
the production of a sound having a tonal pitch, a frequency
composition, and a difference compared to any other gongs.
Although, in the two embodiments described above, at least one
opening 1.2 in the gong 1 is a through-opening, at least one
opening 1.2 in other variants of a gong 1 not illustrated in the
figures could be a blind opening. Likewise, it is possible for a
blind opening 1.2 to have a variable depth, in particular along the
longitudinal axis of the spring blade 1.1. In addition, depending
on the number of openings 1.2, said spring blade may comprise one
or more through-openings 1.2 and/or one or more blind openings 1.2,
without it being necessary to illustrate or describe explicitly all
the possible combinations.
As is clear from the above explanations, due to the fact that the
length and the width of each opening 1.2 can be selected according
to requirements, these openings 1.2 may have a different shape that
will generally be selected depending on the specific requirements
in view of a given gong. An oblong shape of variable length as
illustrated in FIGS. 2a and 2b is one of the preferred shapes of
the openings 1.2 however. The same observation applies to the
positioning of each opening 1.2 along the longitudinal axis of the
spring blade 1.1 of the gong 1, in the sense that this positioning
will be selected as desired according to the requirements for a
given gong 1.
Finally, with regard to the orientation of the openings 1.2 formed
in the main body formed by the spring blade 1.1 of the gong 1, said
openings can be machined in the plane of the movement of the gong 1
during its vibrations, that is to say in the examples illustrated
in FIGS. 1a and 1b in a plane parallel to the plane of the dial or
the plate 4. Each opening formed in the gong can also be formed in
a plane perpendicular to the plane of movement of the gong 1, as is
the case in the embodiments of a gong 1 according to the present
invention illustrated in FIGS. 2a and 2b. These two variants, with
regard to the orientation of the openings 1.2, have the advantage
of being neutral with respect to the longitudinal axis of the
spring blade 1.1 of the gong 1 during its vibrations, provided the
width of the opening is arranged symmetrically about said axis and
the openings are through-openings. These openings therefore only
modify the course of the longitudinal axis of the gong 1 during the
vibrations thereof to a minimal extent. It is nevertheless also
conceivable to form these openings 1.2 at an angle other than
0.degree. or 90.degree. with respect to the plane of movement of
the gong 1 during the vibrations thereof, for example, at an angle
of 30.degree. or 45.degree., provided this allows to obtain the
desired vibratory behavior.
Two other embodiments of a gong for a striking-work mechanism
according to the present invention are illustrated schematically
and by way of example in FIGS. 3a and 3b by perspective views from
above similar to FIGS. 2a and 2b. The gong 1 shown in FIG. 3a
comprises an opening 1.2 in the main body of the spring blade 1.1,
said opening being filled with a material 1.3 other than that in
which the spring blade 1.1 of the gong 1 is fabricated. The gong 1
shown by way of example in FIG. 3b comprises a plurality of
openings 1.2, of which one is filled with a material 1.3 other than
that in which the spring blade 1.1 of the gong 1 is fabricated. The
filling 1.3 of the openings allows to further influence locally and
precisely by two other parameters, that is to say by means of the
rigidity of the filling material and by its mass density, the
rigidity and the weight of the gong 1. The vibratory behavior of a
gong 1 according to the present invention can thus be parameterized
both with the aid of its geometry and its physical properties, that
is to say the material of the main body and the filling material
1.3.
In addition, each opening 1.2 formed in the main body of the spring
blade 1.1 of the gong 1 can only be filled partially by addition of
a material 1.3 other than that of the main body of the gong 1
instead of being filled completely and homogeneously relative to
the outer surface of the gong 1 as illustrated in FIGS. 3a and 3b.
Also, the addition of material 1.3 may protrude slightly beyond the
volume of the cavities formed by the openings 1.2. Said other
material 1.3 serving to fill the openings is preferably gold,
silver, platinum, or a metal alloy of which the Young's modulus and
the density can be adapted. The addition of the filling material
1.3 in the openings 1.2 can be implemented, for example, by
conventional assembly or by material growth or any other equivalent
material deposition method. Generally, it should also be noted in
this context that numerous combinations with regard to the
positioning and also the nature of the filling material are
possible, without the need to illustrate or describe these
combinations explicitly here.
A number of further embodiments of a gong for a striking-work
mechanism according to the present invention are also illustrated,
schematically and also be way of example, in FIGS. 4a to 4c,
likewise by perspective views from above similar to FIGS. 2a and 2b
and 3a and 3b. The gong 1 of the embodiment according to FIG. 4a
comprises openings 1.2 in the main body of the spring blade 1.1 of
the gong 1 and also an inertia-block 1.4 mounted on the spring
blade 1.1 of the gong 1. The gong 1 of the embodiment according to
FIG. 4b comprises openings and also two inertia-blocks 1.4 having
different masses mounted on the gong 1. The gong 1 of the
embodiment according to FIG. 4c comprises a plurality of openings
1.2, of which one opening is filled with a material 1.3 other than
that of the main body, and also an inertia-block 1.4 mounted on the
spring blade 1.1 of the gong 1. Again, the positioning and the size
of the inertia-blocks 1.4 are selected according to requirements. A
person skilled in the art will understand that, in general, a gong
1 according to the present invention comprises at least one opening
1.2 formed in the main body of the spring blade 1.1 of the gong 1,
which may be filled with a material 1.3 other than that of the main
body, and may also comprise at least one inertia-block 1.4 mounted
on the spring blade 1.1 of the gong 1.
The openings 1.2 are preferably machined from the outer surface of
said spring blade 1.1 of the gong 1 by means of a cutting laser 6,
as is illustrated schematically in FIG. 5. The openings 1.2 may
also be formed however by electrical discharge machining, by
micromachining or by water jets, or by any other equivalent
material-removing process. It is also conceivable to use an
ablation laser or any other suitable method in order to produce a
specific structuring of the material located on the surface of the
spring blade 1.1 of the gong 1. In general, the openings 1.2 are
machined from the outer surface of the spring blade 1.1 of the gong
1 by creating a cavity of which the depth is oriented substantially
perpendicular to the longitudinal axis of the spring blade 1.1 of
the gong 1 and which extends along said longitudinal axis.
With regard to the spring blade 1.1 of the gong 1, its cross
section may be substantially circular, oval, rectangular, or
polygonal. Normally, for reasons of simplicity of fabrication, a
wire will be selected as the spring blade 1.1 of the gong 1. The
diameter of this wire is usually in the range from 0.2 mm to 1.2
mm, preferably in the range from 0.4 mm to 0.8 mm. Also, as
mentioned above, in a conventional structure of a horological
striking-work mechanism, the gong 1 will traditionally have at
least partially the form of a circular arc and consists of a wound
wire. The spring blade 1.1 of the gong 1 may only form an
incomplete circle, but may also form an arc of more than
360.degree.. As also mentioned above, it is also possible for the
spring blade 1.1 of the gong 1 to be straight or to have another
specific geometry, the proposed openings 1.2 formed in said spring
blade in fact being machineable from the outer surface of the
spring blade 1.1 independently of the geometry thereof. The same
observation is true for the material of the main body of the spring
blade 1.1 of the gong 1. It is nevertheless preferably fabricated
from a metal material, for example, tempered steel.
Lastly, it remains to be noted that the present invention relates
to any timepiece that comprises a gong 1 according to the present
invention. In particular, it may be a mechanical timepiece, in
particular a bracelet watch, which is equipped with a
striking-work, an alarm, an alert, and/or a repeater mechanism or
any other mechanism requiring a gong.
In view of the detailed description of the structure of a gong
according to the present invention presented above, it is clear to
a person skilled in the art that, besides being a relatively simple
and uncomplicated structure compared to the prior art, a gong
according to the present invention can be provided in a number of
variants and enables versatile use. It is clear that a gong for a
striking-work mechanism having the features mentioned above has the
significant advantage that the geometry and the material
composition of such a gong can be modified locally and precisely,
thus influencing its rigidity, which makes it possible to
determine, when tuning the gong, the vibratory behavior thereof
following an actuation so as to achieve the best ratio between the
time of vibration and the sound volume, that is to say the richness
and the beauty of the sound based on human perception. Due to the
fact that a gong according to the present invention can be adapted
to requirements both by varying the geometry of the gong and, where
necessary, by modifying the material forming the gong, it is
possible to influence with an increased level of precision the
sound produced by the gong, in particular the tonal pitch, the
frequency composition, and also the period of the sound generated.
Such a gong can cooperate in a conventional manner with the other
parts of the timepiece in which it is to be integrated, in
particular with the striking-work mechanism and the rest of the
movement, such that the mechanism can be easily integrated into
existing timepieces without the need for specific adjustments. In
particular, a gong according to the present invention is of the
same size as a corresponding conventional gong, not prompting any
change to its outer dimensions provided the addition of material
does not exceed the volume of the cavities formed by the openings
and provided that no inertia-block is used, whether at the diameter
of its cross section or the diameter of the circular arc of the
gong, in the case of a traditional structure of striking-work
mechanisms. This advantage is very interesting because any increase
in the physical size of the gong would consequently, due to its
movement during its vibration, cause an even more significant
increase in the volume occupied in the watch case. In addition, due
to the relatively simple structure of the gong, these advantages
are obtained by decreasing the occupied volume compared to similar
gongs of the prior art, and by having available methods for
fabricating the gong able to offer both the desired quality in
terms of the sound produced by the gong and also genuine industrial
feasibility of the production process. It should also be noted that
a further advantage of a gong according to the present invention
consists in the fact that it can be applied to all types of
timepieces having a striking-work, repeater watches, alarms,
alerts, pendulums, clocks, etc. Likewise, the invention is not
limited to gongs adapted to be actuated by striking, in particular
by the striking of a hammer, but can also be used for spring blades
actuated by friction, for example for spring blades used in
mechanical music boxes.
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